The answer also could be found in states AIP. Here is extract from ours :
These speeds are applied for ATC separation purposes and are mandatory. Aircraft unable to conform to these
speeds must inform ATC and state what speeds can be used.
In the event of a new (non-speed related) ATC instruction being issued pilots shall continue to maintain the
previously allocated speed. All speed restrictions are to be flown as accurately as possible.
Non-compliance with speed control instructions may lead to an aircraft having to be executed from the planned
approach sequence.